Refrigerator employing secondary refrigeration system



July 26, 19 60 A. e. HELLSTROM REFRIGERATOR EMPLOYING SECONDARYREFRIGERATION SYSTEM Filed Aug. 17, 1956 3 Sheets-Sheet 1 )VZENTOR.

BY; f 7

July 26, 1960 A. e. HELLSTROM 2,946,206

REFRIGERATOR EMPLOYING SECONDARY REFRIGERATION SYSTEM Filed Aug. 17,1956 3 Sheets-Sheet 2 WM /IZVENTOR.

BYg y 7 I y 1960 A. G. HELLSTROM 2,946,206

REFRIGERATOR EMPLOYING SECONDARY REFRIGERATION SYSTEM Filed Aug. 17,1956 Y 5 Sheets-Sheet s United States Patent REFRIGERATOR EMPLOYINGSECONDARY REFRIGERATION SYSTEM Axel 'Gosta Hellstrorn, .lohanneshov,Sweden, assignor to Aktiebolaget Elektroiux, Stockholm, Sweden, acorporation of weden Filed Aug. 17, 1956, Ser. No. 604,711

Claims priority, application Sweden May 14, 1956 7 Claims. (Cl. 62-334)My invention relates to refrigeration, and more particularly concernsthe cooling of the thermally insulated interior of a refrigerator withthe aid of a secondary refrigeration system.

It is an object of my invention to provide an improvement for coolingthe interior of a refrigerator with the, aid of a secondaryrefrigeration system whereby the cooling effect obtained is betterdistributed.

Another object of my invention is to provide an improvement fortransmitting cooling effect to the interior of a thermally insulatedinner shell or liner with the aid of a secondary refrigeration systemoperatively as sociated with primary refrigeration apparatus having acooling element which not only is employed to transmit cooling effect tothe secondary system but also is in heat exchange relation with theinner shell.

A further object of the invention is to provide an improvement wherebyprimary refrigeration apparatus, a secondary refrigeration system and aninner shell form a compact unitary structure which is movable as a unitinto functional relation with the outer shell of a refrigerator cabinetcontaining insulation.

A still further object of the invention is to provide an improvedrefrigerator comprising two units capable of being moved into and out offunctioning relation, the outer shell of the cabinet and insulationtherein forming one of the units, and primary refrigeration apparatus, asecondary refrigeration systemand an inner shell of the cabinet formingthe other of the units.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the claims. The invention, both asto organization and method, together with the above and other objectsand advantages thereof, will be better understood by reference to thefollowing description taken in connection with the accompanying drawingsforming a part of this specification, of which: I

Fig. 1 is a vertical view, partly in section, of a refrigeratorembodying the invention, V 7 Figs. 2., 3 and 4 are enlarged fragmentarysectional viewsof parts shown in Fig. 1 to illustrate details moreclearly;

Fig. 5 is a perspective view of the inner shell or liner of therefrigerator illustrated in Fig, 1 and cooling elementsin thermalexchange relation with the exterior surface thereof; and

Fig. 6 is an enlarged fragmentary sectional view taken at line 5-5 ofFig. 4. 7

Referring toFig. 1, the invention is shown in connection with arefrigerator comprising a cabinet 10 having a one-piece inner metalshell or liner 11 arranged to be supported within an outer metal shell12 and insulated with. any suitable insulating material 14. The innermetal shell. 11 definesa thermally insulated storage space 15 forstoring frozen food. packages and freezing meat, fruit, vegetables andother foods as well as fruit juices and other liquids. Access to thestorage space 15 is afforded through the open top thereof which isadapted to be closed by a removable closure or lid 16 containing a andside walls of the shell by clamps 18 secured thereto,'

as by welding, for example. 7

The evaporator 17 is connected to a condenser 19 which is in heatexchange relation with a low temperature cooling element 20. Theevaporator 17 and condenser 19 connected thereto form a secondaryrefrigeration or heat transfer system, the evaporator being of theflooded type and located at a lower level than the condenser. Theevaporator'l'l and condenser 19 form a closed fluid circuit which ispartly filled with a suitable volatile fluid; such as methyl chloride,ammonia or the refrigerant available under the trademark Freon, forexample, that evaporates'in the evaporator 17 and takes up heat, therebyproducing cold. The vapor flows from the evaporator 17 into condenser 19in which vapor is cooled and condensed by cooling element 20. The liquidcondensate formed in condenser 19 returns by gravity to the'evaporator17.

It will be seen in Figs. 1 and 5 that the evaporator 17 and condenser 19essentially are of helical form with each straight pipe section thereofin heat exchange relation with the outer surface of the inner metalshell 11; Further, the straight pipe sections of the evaporator 17 atthe side walls of the shell are inclined upwardly from the horizontal toform an ascending path of, flow for vapor formed therein. Liquidcondensate flows bygravity to the evaporator 17 in the downwardlyinclined sections of the condenser 19, the pipingforming these parts ofthe secondary heat transfer system being sufficiently large to allowvapor and liquid to pass each other freely. In ad-, dition, thesecondary heat transfer system includes a connection 21 betweenthe lowerend of evaporator 17 and the upper end of condenser 19' which may beprovided with a suitable valve 21a for charging the second system with asuitable volatile fluid.

The low temperature cooling element 20 desirably forms a part of primaryrefrigeration apparatus of any suitable type. Byway of example, theprimary refrigerae tion apparatus may be of an absorption typecontaining an inert gas orpressure equalizing agent. In such apparatus,refrigerant vapor expelled from-solution in a generator 22 byheating'flows through a conduit 23 to a condenser 24in which it isliquefied. The liquid refrigerant, such as ammonia, for example, flowsfrom condenser 24 through a conduit 25 to an upper part of lowtemperature cooling element 20 in which the liquid evaporates anddiffuses in the presence of aninert gas, such as hydrogen,

for example, thereby producing a refrigerating effect for condensingvapor in the condenser 19. p

The resulting gas mixture, of refrigerant'and inert gas flows from theupper end of cooling element 20 through a conduit 26, one passage of gasheat exchanger 27, conduit 28 and absorber vessel 29 to the lower end ofabsorber coil 30 where refrigerant vapor is absorbed into liquidabsorbent, such as water, which enters through a conduit 31. Inert gasweak in refrigerant is returned to cooling element 20 in apath of flowincluding conduit 32, another passage of gas heat exchanger 27 and aconduit 33. Absorption liquid enriched in refrigerant in the absorber30- passes into the absorber vessel 29: and flows therefrom through aconduit 34 to generator 22 where it is heated and refrigerant vaporagain is expelled. out of solution. The weakened absorption liquid fromwhich refrigerant. haslieen'expelledas vapor. is conducted from thegenerator 22 through conduit 31 to again absorb refrigerant vapor. Itwill be seen that a part of conduit 25 is in heat exchange relation withthe gas heat exchanger 27 to effect pre-cooling' of liquid refrigerantin its path of flow from condenser 24 to the upper end of coolingelement20. Further, the portion '25a of. conduit'25 may be arranged in heatexchange-relation with conduit 26 through which the cool mixture ofrefrigerant vapor and inert gas flows upon leaving cooling'element 20,thus effecting additional cooling of liquid refrigerant before it entersthe cooling element in the presence of the inert gas.

The upper end of conduit 26 is formed with raised portion or hump 26a toinsuredownward flow of liquid refrigerant in the cooling element 20.

- In order to simplify the drawings, part of the primary refrigerationapparatus has been shown only diagram matically, apparatus of this typewhich includes provisions to insure upward flow of inert gas through thecooling element 20 in counterflow to liquid refrigerant being wellknown.

. The parts of the primary refrigeration apparatus just described, whoserelative positions are substantially fixed, usually are formed of ironor steel when ammonia and water are employed as the refrigerant andliquid absorbent, respectively. Therefore the piping for the coolingelement 20 which is connected by conduits to other parts of the primaryrefrigeration apparatus and forms a unitary part thereof may be formedof such ferrous metal.

In accordance with my invention, inorderthat the assembly of parts willbe compact and provide a refrigerator of a given capacity which willoccupy a minimum amount of space, the cooling element 20, which is inheat exchange relation with the condenser 19 of the secondary heattransfer system, is arranged in heat exchange relation with the innermetal shell or liner 11 of the cabinet 10. As best shown in Figs. 5 and6, the primary cooling element 20 comprises piping disposed about thefour sides of the inner liner 11, the piping being disposed alongside ofand in heat exchange relation with the condenser 19 of the secondaryheat transfer system. The primary cooling element 20 and condenser 19may be fixed to the exterior surface of the inner liner 11 in anysuitable manner, as by clamps which are secured thereto at 36 and 37, asby spot welding, for example, as shown in Fig. 6. In this way, theprimary cooling element 20 and condenser 19 are held in good heatexchange relation with one another and the outer surface of the innerliner 11. During normal operation of the refrigerator illustrated in thedrawings and just described, heat is effectively abstracted from theinterior of space 15 by the evaporator 17 of the secondary heat transfersystem in the manner explained above. Inaddition, the primary coolingelement is advantageously employed to abstract heat from the upper partof the space 15 by virtue of its location at the upper part of thesecondary heat transfer system. By transmitting cooling effect in thismanner to the storage space 15, the vertical temperature gradient in thelatter is reduced sharply, particularly when the storage space isloaded. Accordingly, it is possible to increase the height to whichfrozen food packages can be safely stored in storage space 15 withoutany thawing of frozen food packages in the uppermost layer, and withoutplacing an additional burden on the primary refrigeration apparatus tomaintain the storage space at the desired low mean or averagetemperature.

Also, if the secondary heat transfer systemshould fail and renderevaporator 19 ineifective to transmit cooling effect to the storagespace 15 and its contents, the foodstuffs in the storage space willstill be protected since primary cooling element 20 will still beoperable to transmit cooling effect to the interior of the storagespace.

In order to facilitate servicing and inspection of therefrigerationequipment, particularly the secondary heat transfer system which forms aunitary part of the primary refrigeration apparatus, the refrigerationequipment is mounted in the cabinet 10 in such a manner that it and the.

inner metal shell 11 can be removed as a unit from the outer shell ofthe cabinet. Accordingly, the refrigeration equipment forms a unitarystructure which includes the inner liner or shell 11 and a plate 38which is fixed to parts of the primary refrigeration apparatus in anysuitable manner (not shown).

The plate 38 forms the outside panel of the rear insulated wall of thecabinet 10, the lateral side walls 12a and top 12b of the outer shell 12extending or projecting beyond the plate 38 to provide a verticalcompartment 39 in which parts of the primary refrigeration apparatus arehoused. During operation of the primary refrigeration apparatus, naturaldraft circulation of air is induced in compartment 39 to effect aircooling of the absorber 30 and condenser 24, such cooling air flowingupwardly in the compartment and passing therefrom through openings (notshown) at the rear part of the top 121) of the cabinet.

The cabinet 10, which includes a base 41, is so constructed that theinner liner 11, which forms a unitary part of the refrigerationequipment, can be readily removed from the cabinet and placed back inposition whenever necessary. Referring to Fig. 1, the cabinet 10includes a base 41 which is formed in part by the front wall 12c andlateral side walls 12a of the outer shell 12. A horizontal plate 42forming the outer panel of the bottom insulated wall is fixed to thefront and lateral side walls of the outer shell 12 and also to thebottom part of a vertical panel 43 having an opening thereinsufliciently large for the inner liner 11 to pass therethrough, thepanel 43 also being fixed to the top 1% and lateral side walls 12a ofthe outer shell.

The bottom part of the rear vertical panel 43 is provided with an anglemember 44a which is at a slightly higher level than an angle member 44bfixed to theinner surface of the front wall 12c of the outer shell. Apair of U-shaped members 45a and 45b are fixed to the angle members 44aand 44b, respectively, for holding a pair of elongated bars 46 which areemployed to support the bottom of the inner liner or shell 11. Theclosed ends of the U-shaped members 451) are fixed to the inside surfaceof the front wall 12c of the outer shell, and the closed ends of theU-shaped members 45a are fixed to the angle member 44a, thus providingsupporting places at substantially the same height for the ends of thebars 46 which may be formed of any suitable material having poor thermalconductivity, such as wood, for example.

In order to simplify the drawings, the gas heat exchanger 27 of theprimary refrigeration apparatus has been illustrated in Fig. 5 as anessentially straight component or part of the system. To provide acompact arrangement of parts, it is advantageous to employ a gas heatexchanger which is bent intermediate the ends thereof, a first section27a of which is embedded in the insulation of the rear insulated wall ofthe cabinet and extends lengthwise thereof and a second section 27b ofwhich is perpendicular to the first section and extends rearwardly intothe vertical apparatus compartment 39, as shown in Fig. l.

The conduit connections in Fig. 1 corresponding to conduits 26 and 33 inFig. 5 serve to support primary cooling element 20 and inner liner 11 onthe inner section 27a of the gas heat exchanger 27. Also, a member 47may be fixed to a lateral side wall of the inner liner 11 and to the gasheat exchanger 27, respectively, to provide additional support for theinner liner on the primary refrigerating apparatus. Further, a bridgingmember 48 formed of suitable insulating material, such as wood, forexample, may be located between the rear wall of the inner liner 11 andthe plate 38, such bridging member 48 being fixed to these parts at 49and 50, respectively.

The top opening of cabinet 10 is defined by a frame 51 of annular formwhich may be made of suitable insulating material, such as wood, forexample. The frame s na ed at 52 o one am o a! e be 53 of as asaaaoeshape; the other armof which is'secured, as by welding; to the undersideof the top 12b of the cabinet at the vicinity of the opening therein.

Each of the three sides of frame 51 at the front and lateral. sides ofcabinet is formed with a groove 54 which receives an outwardly extendingflange He at the top open end of the inner liner 11, as best shown inFig. 2. The side of frame 51 at the rear of the cabinet is of shorterdepth than the other three sides and the bottom side 51a terminates atabout the level of the grooves 54 to provide a space54a whichreceivesone side of the outwardly extending flange 11a of inner liner 11, asbest seen in Fig. 3. To form a good seal between the frame 51 and flange11a of the inner liner 11, a suitable sealing material 54b, such. asthat sold under the trademark, Permagum,. for example, desirably isforced into the grooves 54 and space 54a. A finishing strip 55 which isresilient in character and may be. formed of plastic material desirablyis positioned about the frame 51, the strip 55 having a lip 55a which isheld in place at the peripheral edge of the opening in the top 12b ofthe cabinet. The bottom part of the strip-55' may be removably securedat 56 to the frame 51.

Essentially, the refrigerator illustrated in the drawings and describedabove comprises two main units or com ponents which are readilyseparated whenever inspection or, repair of the refrigerating system isnecessary. One component comprises the base 41, outer shell 12 andinsulation 14 retained therein at the bottom, front and lateralsidewalls, and the other component comprises the primary refrigerationapparatus, secondary heat transfer system, inner liner 11 and insulationfor the rear insulated wall of the cabinet 10. The plate 38, whichforms, the outside panel of the rear insulated wall of the refrigeratorcabinet 10 and is fixed to and form a unitary part of the parts makingup the primary refrigeration apparatus, is removably secured at 38a tothe apertured vertical wall member 43, as best shown in Fig. 4.

When it becomes necessary to inspect or repair the refrigerating system,the finishing strip 55 is detached and the sealing material 54b removed.The connections 38a at the rear insulated wall of the cabinet 10 areloosened, which then allows the primary refrigeration apparatus,secondary heat transfer system, inner liner 11 and insulating" materialbetween the rear wall of the inner liner 11 and the vertical plate, 38to be moved as a unit. It will be: understood that when this is done,the part of flange 11a of the inner liner 11 which is at the vicinity ofspace 54a can immediately move rearwardly, while the remaining parts offlange 11a can freely detach themselves from the grooves 54 in the othersides of the frame 51. After the initial rearward movement of the plate38, it may be necessary to compress the insulation at the rear wall ofthe cabinet about the opening in plate 43 in order to work it free andallow it to pass without diificulty, along with the secondary heattransfer system and inner liner 11, through the opening in the plate 43.

When the two units or components of the refrigerator are reassembled andbrought together in functioning relation, the insulation is positionedbetween the inner liner 11 and plate 38 in the event it has beenremoved, and the inner liner 11 is inserted through the opening in theplate 43 and positioned on the elongated bars 46. After tucking in theinsulation about the opening in the plate 43, the connections 38a forplate 38 are tightened. With the flange 11a of inner liner 11 nowcorrectly positioned at the vicinity of the frame 51, sealing material54b, desirably having the physical characteristics of a non-dryingcement, may again be inserted in the grooves 54 and space 54a to effecta seal between the frame and inner liner 11, after which the finishingstrip 55 may be connected about the frame opening.

In view of the foregoing, it will now be understood that an improvedrefrigerator has been provided which is extremely compact and can bereadily repaired or examined when necessary. Although not shown, it willbe understood that all of the seams of the outer; shell 12 of the.cabinet may be internally sealed with a, suitable material;

like asphalt, for example. Such a sealing material may be employed, forexample, at the bottom side of member- 53 to seal the latter to theunderside of the top 12b of the cabinet 12 and to the frame 51. Mineralwool or like material in the form of batting trimmed to fit theinsulating wall sections at the bottom, front and lateral side: walls ofthe outershell 12 may be used for the insulation 14, in which case thebars 46 are placed in position after. the bottom insulating section hasbeen placed against the bottom plate 42. The insulation between theinner liner 11 and plate 38 may be of the same kind as that used in theother walls of the cabinet 10. A suitable scaling agent 38b, like theseahng agent 54b, may also be employed at the peripheral edge of plate38 when the latter is secured in place by the connections 38a to providean airtight seal for the insulation retained in the cabinet 10.

Modifications of the embodiment of my invention which I have describedwill occur to those skilled in the art, Therefore, as I desire myinvention not to be limited to the particular arrangement set forth, I-intend in the claims to cover all those modifications which do notdepart from the spirit and scope of the invention.

What is claimed is:

1. A refrigerator comprising a cabinet having spaced apart inner andouter shells and insulating material therebetween of which a partthereof, is removable, said inner shell defining a space to be cooled,primary refrigeration apparatus comprising a coolingelement disposedexteriorly of said space, a secondary heat transfer system disposedexteriorly of said space which, contains a refrigerant and includes acondenser in heat exchange relation with said cooling element and anevaporator arranged to abstract heat from said space, the aforementionedparts comprising two units movable into and out of functioning relation,one of said units comprising said outer shell and a major porton of theinsulating material and the other of said units comprising unitarystructure including said primary refrigeration apparatus and secondaryheat transfer system and inner shell, said other unit being movable withrespect to said one unit in apath which includes a zone normallyoccupied by the-removable part of the insulating material, said outershell including a wall member having an opening and a hollow frame fixedto such wall member at the opening therein, said inner shell having anopening which is at the vicinity of said frame when said units are movedintofunctioning rela tion,the openings in the inner and outer'shells andhollow frame at the vicinity of the openings defining an access passageto said space, said inner shell at the vicinity of the opening thereinhaving an element, and said hollow frame having a surface-engaging partwhich is engaged by said element when said units are in functioningrelation.

2. A refrigerator comprising a cabinet having spaced apart inner andouter shells and insulating material therebetween of which a partthereof is removable, said inner shell defining a space to be cooled,primary refrigeration apparatus comprising a cooling element disposedexteriorly of said space, a secondary heat transfer system disposedexteriorly of said space which contains a refrigerant and includes acondenser in heat exchange relation with said cooling element and anevaporator arranged to abstract heat from said space, the aforementionedparts comprising two units movable into and out of functioning relation,one of said units comprising said outer shell and a major portion of theinsulating material and the other of said units comprising unitarystructure including said primary refrigeration apparatus and secondaryheat transfer system and inner shell, said other unit being movable withrespect to said one unit in a path which includes a zone normallyoccupied by the removable part of the insulating material, said outershell having a first opening through which said primary cooling 7element-and secondary heat transfer system and inner shell pass whensaid units are moved into and out of functioning relation, said outersliell having a second opening, said inner shell having an opening atthe vicinity of and spaced from the-second opening of said outer shellwhen said units are in functioning relation, and bridging means to closethe gap between the second opening in said outer shell and the openingin said inner shell. 3. Apparatus as set forth in claim 2'. in whichsaid inner liner and its opening define a space having a top accessopening, said cooling element being heat conductively connected to saidcondenser and also to the exterior surface of said-inner shell, and saidevaporator being disposed at a lower level than said condenser and heatconductively connected to the exterior surface of said inner shell.

- 4. A refrigerator comprising a cabinet having spaced apart inner andouter shells and insulating material therebetween of which a partthereof is removable, said inner shell defining a space to be cooled,primary refrigeration apparatus comprising a cooling element disposedexteriorly of said space, a secondary heat transfer system disposedeXter-iorly of said space which contains a refrigerant and includes acondenser in heat exchange relation with said cooling element and anevaporator arranged to abstract heat from said space, the aforementionedparts comprising two units movable into and out of functioning relation,one of said units comprising said outer shelland a major portion of theinsulating material and the other of said units comprising unitarystructure including said primary refrigeration apparatus and secondaryheat trans fer system and inner shell, said other unit being movablewith respect to said one unit in a path which includes a zone normallyoccupied by the removable part of the insulating material, said outershell including a wall member having an opening and a frame fixed tosuch wall member at the opening therein, said inner shell having anopening which is at the vicinity of said frame when said units are movedinto functioning relation, the openings in the inner and outer shellsand frame at the vicinity of the openings defining an access passage tosaid space, said frame being rectangular and having a groove at at leastthree sides thereof, said inner shell at the vicinity of the openingtherein having an outwardly directed flange received by said groove whensaid units are in functioning relation.

5. A refrigerator comprising a cabinet having spaced apart inner andouter shells and insulating material therebetween of which a partthereof is removable, said inner shell defining a space to be cooled,primary refrigeration apparatus comprising a cooling element disposedexteriorly of said space, a secondary heat transfer system disposedexteriorly of said space which contains a refrigerant and includes acondenser in heat exchange relation with said cooling element and anevaporator arranged to abstract heat from said space, the aforementionedparts comprising two units movable into and out of functioning relation,one of said units comprising said outer shell and a major portion of theinsulating material and the other of said units comprising unitarystructure ineluding said primary refrigeration apparatus and second aryheat transfer system and inner shell, said other unit being movable withrespect to said one unit in a path which includes a zone normallyoccupied by the removable part of the insulating material, said outershell including one Wall member having a first opening through whichsaid primary cooling and secondary heat transfer system and inner shellpass when said units are moved into and out of functioning relation,closure means for closing the first opening when said units are infunctioning relation, said outer shell including another wall memberhaving a second opening, said inner shell having an opening at thevicinity of and spaced from said second opening when said units are infunctioning relation, and bridging means to close the gap between thesecond opening in said outer shell and the opening in said inner shell.

6. Structure as set forth in claim 5 which includes means for sealingsaid closure member to said one wall member at the first opening and forsealing said -bridg-. ing means to said inner liner at the openingtherein.

7. Structure as' set forth in claim 6 in which said closure means forclosing the first opening forms a unitary part of the other of saidunits, and removable fastening means for connecting said closure meansto said one wall member to close the first opening, said fastening meanscomprising the primary fastening provisions for holding said units infunctioning relation. 7 7

References Cited in the file of this patent UNITED STATES PATENTSTandberg Aug. 25, 1953

